Genetics

Genetics is the brnach of biology which studies genes, genetic variation, and heredity in organisms.

Origins
The study of genetics originated during the 19th century. One of the early theorists, Jean-Baptiste Lamarck, argued that animals inherited their parents' traits. However, modern genetics begins with Gregor Mendel (who studied the traits of pea plants over several generations) and Charles Darwin (who devised the concepts of evolution and natural selection) in the late 19th century. The ideas of natural selection led to some prematurely concluding that it was also natural in human society to adapt to survive, leading to the rise of Social Darwinism and eugenics. Both of these movements, which were pioneered by the conservative white (in the United States, WASP) elites, would largely die out as a result of the Great Depression and World War II.

Modern genetics: 1925 to 1960
By the beginning of the 20th century, it was established that there were units of inheritance within the cell, these units somehoow held the information which guided the development of the organism (and were involved with the evolution of life on the planet), there were patterns to the inheritance of these units that followed some underlying guiding mathematical principle (Mendelian genetics), that some traits seemed to be complex in their inheritance through an interaction of many of the units with the environment (Francis Galton's theory of polygenetic inheritance), that these units of inheritance were located within the cell (most likely on the chromosomes, as per the Chromosome Theory of Inheritance), and that the idea of these units of inheritance was so powerful that this concept of the gene had influenced the social and political progams of nations.

What was not known as what exactly the gene was and what it was made up of, how it contained the information of inheritance, how its information traveled from a parent to the offspring, how it changed and mutated, how it expressed the information, and how the gene was influenced by the environment. The period of time at the beginning of the 20th century is scientifically spectacular, and the answers to many of the questions started to emergy.

Discovery of DNA
The quiet, educated physician Friedrich Miescher, who was interested in clotting and bacterial infections, especially pus. He decided to look into what it was made of, exposing it to chemicals. He found out that, in the pus, nucleic acid, and in the nucleus, there was a material that would precipitate out of the cells. He discovered a fluffly substance, which he called nuclein (now known as DNA). In 1928, Frederick Griffith discovered that in heat-killed, disease-causing bacteria, there was a factor which could change harmless bacteria into disease-causing bacteria, "bacterial transformation". Non-virulent bacteria could be transformed into virulent bacteria by the contact between the remnants of dead virulent bacteria with active harmless bacteria. For the first time, people were able to control a movement of chemicals holding units of inheritance.

Griffith found that some molecule or molecules held the ability to transmit genetic information, but wondered what it was. Science showed that the cell was composed of many different classes of molecules - the molecules of life, sugars (carbohydrates), fats, proteins, and nucleic acids. Of the major classes, proteins were by far the most diverse. Proteins were in almost every function of the cells, and there were literally thousands of different types of proteins in the cell, doing almost every function in the cell, they were generally thought of as the "work horse" of the cell. They were enzymes, structural elements, hormones, and movers of other molecules. They were molecular components of the chromosomes (along with nucleic acid), and were generally believed to be the most likely molecular candidate to be the genetic material.

However, all of these theories changed when Oswald Avery decided to find out what exactly was Gfirrifht's transforming agent. Erwin Chargaff wanted to learn more about the chemical nature of the molecule called DNA in New York City at Rockefeller University and at Columbia University, and he discovered that all DNA has the same type of sugar, that it has four nitrogen bases, that adenine is always equal to thymine (a=t) and that cytosine is equal to guanine (c=g), and that "a+t/g+c" will have different results for each species due to differing traits and ratios in each species.